The invention relates to the high-speed, high-volume conveying of small articles which are to be sorted by being conveyed from a loading station to one of a number of collecting stations disposed along a conveying path. In particular, the invention relates to the loading station.
Such a conveying/sorting apparatus is used to sort articles such as packages in mail-order facilities and courier services, for example. The apparatus typically includes a rail which defines the conveying path, and a number of transport devices which travel along the rail between the loading and collecting stations. Each transport device includes a platform, such as a driven endless belt, which receives articles at the loading station and discharges them onto collection devices at respective collection stations.
Various types of conveying/sorting machines are known; in particular, commonly owned patent GB 2,111,933, relates to a sorting plant which comprises a number of transport devices or trucks, each having a rotation apron or belt constituting an article transport and unloading platform. The trucks move along a fixed route lined with containers designed to collect, and thereby sort, the articles. The articles, suitably coded on the basis of their destination, are loaded into individual cells in a loading station where sensing devices (e.g., scanners) check the type of parcel (size, weight, etc.), match each parcel with a transport platform, and load the articles into respective trucks passing through the loading station. The articles are actually introduced into the transport platforms by means of loading conveyor units which are suitably synchronized and controlled in terms of both speed and acceleration in order to produce precise movement of the articles. Such loading units are also known, being described in commonly owned patent EP 0 343 613.
Developments in the technology and the application of sophisticated types of electronic apparatus for the management of these plants have produced a considerable increase in productivity, with the result that a plant with some 300-400 transport platforms can sort over 10,000 objects an hour.
However, users' requirements have kept pace with developments in the technology, and increasingly precise units with higher productivity are required. A particularly interesting way of obtaining a high-productivity plant with a large number of outputs is to construct a conveying/sorting apparatus in which each transport device carries vertically superimposed transport platforms in the form of rotating aprons, each of which is loaded with an article to be sorted along the conveying route. The collection devices are also installed on two levels, at the respective heights of the aprons, as disclosed in commonly owned, concurrently filed, U.S. application Ser. No. 08/749,230, of Tacchi the disclosure of which is incorporated by reference herein.
That dual-platform system enables twice the number of articles to be handled in a given period of time without increasing the number of conveyor trucks or the size of the plant. However, it poses the problem of how to load the articles onto transport platforms disposed at different levels without requiring separate loading stations, one for each level, and without having to make extensive, costly modifications to the structure of the plant.